As well known to those skilled in the art, a variable intake system adjusts the length of a runner of an intake manifold, through which air to be drawn into a combustion chamber passes, depending on the engine operating conditions, thus enhancing the performance of the engine.
To adjust the length of the runner through which intake air passes, a plurality of valves is rotatably provided on a valve shaft in the intake manifold assembly. A plurality of retainers and a plurality of locking bolts are used for installation of the valve shaft.
The retainers and locking bolts to be used for retaining the valve shaft must stably support the valve, and the stable installation state must be maintained.
The information set forth in this Background of the Invention section is only for enhancement of understanding of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art that is already known to a person skilled in the art.